Spray nozzle device for cleaning accumulations in suction roll openings

ABSTRACT

Method and apparatus for removing accumulations of fibers, rosin, clays, etc., from the openings in suction rolls used in the production of paperboard. Jets of water from nozzle openings impact the accumulations in a radially inward direction and unplug the suction roll openings. The ratio of diameters of the suction roll openings to the diameter of the nozzle jet openings is approximately 5.35 to 1. The water is supplied to the nozzle at a pressure of the order of 150 to 200 p.s.i., and each nozzle opening projects a jet of water such that each of the suction openings is independently subjected to the entire impact of the jet.

United States Patent Inventor James T. Farrell Schuylerville, N.Y.

Appl. No. 754,704

Filed Aug. 22, 1968 Patented Nov. 2, 1971 Assignee United Board 8: Carton Corporation Ridgelield Park, NJ.

SPRAY NOZZLE DEVICE FOR CLEANING ACCUMULATIONS IN SUCTION ROLL OPENINGS 13 Claims, 4 Drawing Figs.

u.s.c1 162/199, 134/21, 134/23, 134/34,134/172. 162/278,

lnt.Cl 112111/34, B08b 3/02, B08b 9/00 Field oISearcII 162/272,

1,594,306 7/1926 Lenz et al. 162/277 FOREIGN PATENTS 665,506 6/1963 Canada Primary Examiner-S. Leon Bashore Assistant Examiner-R. H. Tushin Attorney-Curtis, Morris 8; Safford ABSTRACT: Method and apparatus for removing accumulations of fibers, rosin, clays, etc., from the openings in suction rolls used in the production of paperboard. Jets of water from nozzle openings impact the accumulations in a radially inward direction and unplug the suction roll openings. The ratio of diameters of the suction roll openings to the diameter of the nozzle jet openings is approximately 5.35 to 1. The water is supplied to the nozzle at a pressure of the order of 150 to 200 p.s.i., and each nozzle opening projects a jet of water such that each of the suction openings is independently subjected to the entire impact of the jet.

SPRAY NOZZLE DEVICE FOR CLEANING ACCUMULATIONS IN SUCTION ROLL OPENINGS This invention relates to paper making, and particularly to the cleaning of suction rolls of paper machines of the type used for producing paperboard.

An object of this invention is to provide for the cleaning of the holes in a suction roll in an extremely simple, efficient and dependable manner. Another object is to provide means for cleaning the suction roll on a paperboard machine while the machine is operating. A further object is to provide for the above in a manner which will not interfere with the normal operation of the machine. These and other objects will be in part obvious and in part pointed out below.

ln paperboard machines there are suction rolls into which water is drawn from the completed web of paperboard as that web passes between two layers of felt. Such a suction roll is typically a thick metal cylinder having a larger number of radial holes which are small and closely spaced and through which the water is drawn into a suction box. Those holes become plugged, or substantially closed, by materials such as rosin which is used for sizing in certain papers, small pieces of felt fibers, clay, starch, etc. in the past, it has been accepted practice to shut down a paperboard machine from time to time and to drill the materials from the holes in the suction roll. That procedure is time consuming and expensive, and it necessitates removing the machine from service for a substantial period of time, thus seriously interfering with the normal production of paperboard. Furthermore, there is a tendency to continue operating the machine even after the holes in the suction roll have been substantially closed. Hence, the machine operates very satisfactorily for a period of time after it has been shut down and the suction roll has been cleaned, but there comes a time when the holes start to become clogged and that interferes with the proper operation of the machine. It is an object of the present invention to provide an efficient and dependable system for cleaning the holes on suction rolls without shutting the machine down and, in fact, without interfering with the normal operation of the machine. ln accomplishing that object it has been found that a paper machine may be maintained in optimum operating condition at all times. That is, the suction roll is cleaned more frequently than has been the practice in the past and the holes in the suction roll are not permitted to become plugged sufficiently to interfere with the desired operation.

In accordance with the present invention, the materials accumulated in the holes in the suction roll are removed by projecting small jets radially inwardly against the outer surface of the moving roll. Such a jet of water projected against the roll impacts the materials in the holes which move into axial alignment with the jet. That impacting action erodes the materials and very quickly cleans the hole. Hence, as the roll turns, the jet of water cleans each of the holes in alignment with it. In the illustrative embodiment of the invention, a small number of jets of water are used and they are moved step by step across the roll, cleaning the holes progressively from one edge (or end) of the roll to the other.

Referring to the drawings in which one illustrative embodiment of the invention is shown:

FIG. 1 is a schematic representation of the portion of the paperboard machine in the vicinity of the suction roll;

FIG. 2 is a section of the mechanism at the line 2-2 of HG. l; and.

FIGS. 3 and 4 are views on the lines 3-3 and 4-4, respectively, of FIG. 2.

Referring to FIG. 1 of the drawings, there is shown diagrammatically the portion of a standard type of paperboard machine which includes a suction roll 2 having a large number of closely spaced radial holes 3 therein, and positioned above roll 2 is a rubber-covered and weighted roll 4. Passing to the right between rolls 2 and 4 are two endless felts 6 and 8 and between them is a web 10 of paperboard. Web l is built up on felt 8 from layers formed on a series of spaced wire cylinders which are not shown. Web is then carried upwardly (at the left of HO. 1) by felt 8, and felt 6 moves downwardly onto the top of web 10 at the bite 12 between the rolls. Roll 4 is swingably mounted and its weight urges it downwardly so that two layers of felt and web 10 are pressed against suction roll 2 by the action of gravity on roll 4. Positioned beneath bite 12 is a suction box 14 which has sealing strips at its edges so as to maintain a suction condition on the inside surface of the suction roll in the vicinity of the bite and to the right for a short distance. The pressure of roll 4 squeezes water from web 10 and felts 6 and 8, and the suction draws the water through holes 3 into the suction box. The water is withdrawn and the suction condition is maintained by connections through the end of the suction roll. Felts 6 and 8 carry web 10 to the right for the completion of the manufacturing process. All of the above construction and its operation are well known in the art and constitute an illustrative embodiment of a known type of suction roll assembly in a paperboard machine.

Positioned adjacent roll 2 to the right of bite l2 and suction box 14 is a roll-cleaning unit 16 which projects jets of water radially inwardly against the outer surface of roll 2 immediately after the roll surface moves away from felt 8. Unit 2 ineludes a stationary horizontal tube 18 which extends through the machine from one side to the other with its axis parallel to the axis of roll 2, and which is rigidly mounted at its end; illustratively on brackets 20. Referring to FIG. 2. tube 18 provides a rigid support for a cylindrical nozzle head 22 which is adapted to slide longitudinally of tube 18 substantially the width or longitudinal dimension of roll 2.*Referring to FIGS. 3 and 4, tube 18 has a longitudinal slot 24 and, mounted in nozzle head 22 are three nozzles 26, 28 and 30. Mounted on nozzle head 22 respectively between the nozzles, are two guide blocks 32 which are clamped by stud bolts 34. As shown best in FIG. 4, each of the guide blocks 32 extends the width of slot 24 so that they hold the nozzle head and, in turn, the nozzles in a precise, predetermined relationship; and yet the nozzle head with the nozzles may be moved longitudinally of tube 18 from one end of slot 24 to the other. As shown at the lower portion of FIG. 2, a pipe 36 is threaded into the end of nozzle head 22 and the other end of the nozzle head is closed by a screwplug 38'. Referring again to HO. 1, pipe 36 extends beyond the side of the machine and is connected to a reinforced flexible hose 38 through a rightangle coupling 40. Hose 38 is connected to a source of water 39 at high pressure so as to supply water to the nozzle head. However, coupling 40 also acts as a handgrip by which the nozzle head is moved manually along the roll 2 during operation to clean the roll.

in FlGS. 2 and 3, nozzle 30 is shown in section and the other nozzles are identical with it. Nozzle 30 has a nozzle opening 42 through which the small jet of water is directed from the nozzle head. The other characteristics of the nozzles are standard. The small jet of water is directed radially inwardly toward the outer surface of roll wall 2. When the jet is in alignment with one of the holes 3, it impacts against any material within the hole. In this embodiment, water is supplied to nozzle head 22 at a pressure of the order of to 200 pounds per square inch, and the circumferential speed of roll 2 is 300 feet per minute. When one of the jets impacts the roll surface the water is deflected and falls downwardly. However, when one of the holes 3 moves into alignment with a jet, the water is projected into it very rapidly and with great force. That impact is instantaneous, but it has been found that it acts to clean the hole of any accumulated materials. If the hole is clean, then the water projected into it moves on beyond the inner surface of the roll wall. if the hole is completely or partially closed. the water is stopped but the impact produces a certain amount of erosion of the accumulated material. However, immediately the hole moves past the water jet and the centrifugal action tends to throw the water out of the hole. Hence (see FIG. 1), even if water has been projected through a hole it may be thrown out again by the centrifugal action prior to the next contact with felt 8. Hence, the positioning of unit 16 as shown aids in disposing of the water.

Referring again to FIG. 2. each of the nozzles is illustrated as all being simultaneously in alignment with a hole 3, although in actual practice, that might not occur. However, holes 3 are in a staggered pattern so that there are some holes substantially in alignment with each jet at all times. It should be noted that the jets of water do not damage roll 2 and that there are no harmful results from projecting a jet against the roll surface or through a hole which is clean. in carrying out the cleaning operation, the operator takes hold of coupling 40 and moves the nozzle head to one end of slot 24, e.g., so that nozzle 26 is positioned at the end 25 of the slot, and in that position its nozzles are in alignment with holes near the edge of the pattern of holes. The water is then turned on and the jets are projected against the roll. The nozzle head is left in that position until the rows of holes in alignment with the nozzles have been cleaned, and the nozzle head is then moved a short distance manually. Hence, the nozzle head is moved step by step across the roll, and between each step and the next a row of holes is cleaned. For at least some conditions of operation the jets produce a heavy fog when they are projected against holes which are partially or completely plugged, whereas there is very little fog and mainly a surface splashing when the holes are clean. With that mode of operation, the operator merely observes the area of the nozzles and can readily determine whether or not the .holes are clean, and when they are the nozzle head is moved to a new location. In the illustrative embodiment thesteps of movement are of the order of one-eighth inch. The utilization of three nozzles insures thorough cleaning of the hole of the present embodiment. When the nozzle head is moved step by step in the direction from the top to the bottom of FIG. 2, either of nozzles 26 or 28 may be moved into alignment with the row of holes which has been cleaned by nozzle 30. However, that has no harmful effect.

The invention contemplates that the nozzle head may be moved in accordance with a timed program, either in place of or in conjunction with having the operator observe the "fog effect" which is discussed above. Also, automatic means may be provided to move the nozzle head with a step-by-step movement or by a slow, constant movement. Also, more or less than the three nozzles may be usedand a single nozzle head or the equivalent may have nozzles spaced far apart across the suction roll.

In the above discussion certain details are set forth as to the construction and operation of the illustrative embodiment of the invention. Suction roll 2 is of bronze with an outside diameter of 29 inches and a wall thickness of the order of 1 inch. The nozzles are positioned with a maximum of Vz-inch spacing between the roll surface and the annular surfaces 31 on the projecting ends of the nozzles. Holes 3 are 96 inch in diameter with a spacing of inch to 56 inch between the axes of two adjacent holes. Hence, the roll surface along a line between the axes of two adjacent holes is of the order of Vt inch or less. The area of the pattern of holes in the roll is 120 inches wide, and within that area there are more than 100,000 holes. With the prior procedure for cleaning this particular roll the machine was stopped and each hole was drilled. [t is apparent that that consumed many working days and it was necessary to clean the roll approximately every 4 months. With the present invention, that same roll has been thoroughly cleaned in 5 hours while the machine continued to produce paperboard in its normal manner.

It has been indicated above that the nozzles are of standard design. The nozzle opening or hole 42 in each of the nozzles is the size of a No. 50 drill which is 0.07 inch. With the suction roll holes having a diameter of 5i: inch and the nozzle holes having a diameter of 0.07 inch the ratio of diameters is approximately 5.35 to I. In the drawing in this application the structure of unit 16 is shown in full scale and with accuracy with respect to the shapes and relative positions of the parts. Hence, to that extent the drawing may be relied upon as a detailed disclosure of the illustrative embodiment of .the invention. For example, referring to FIG. 3, it will be noted that the extreme end of nozzle 30 is #6 inch from the outer periphery of suction roll 2. With that position the jet of water from the jet opening 42 is projected a distance of the order of 1 inch before it reaches the roll surface or projects into an opening 3 in alignment with it. Hence, when the nozzles are positioned the maximum distance of the order of 1% inch from the roll surface the free jet of water is projected a distance of the order of 1% inches, and tests have indicated that this distance should not be greater than the order of 1% inches.

The invention is shown herein with a particular type of machine for producing coated and uncoated paperboard. It should be understood that the invention may be used with other machines where the same or similar problems are present. In general, the terms suction roll and suction drum" are used interchangeably to identify a roll having a thick cylindrical wall with spaced radial suction holes through which water is withdrawn from the paperboard web and the supporting felt. Similar rolls and other constructions are used in machines where the operating conditions cause materials to accumulate and produce stoppages, and where the present invention may be used advantageously.

What is claimed is:

1. in the art of cleaning materials from a suction roll in a papermaking machine said suction roll being free of any felt wrapped wholly therearound, said roll having radial suction openings within which the materials tend to accumulate so as to impair the operation of the machine, the steps of, rotating said roll, projecting a compact jet of water at a pressure of not less than 150 psi. toward the axis of said roll from a zone adjacent to and spaced radially outwardly from the peripheral surface of the roll, impacting said compact jet of water against the surface of the roll and individually into each of said openings as said openings are sequentially presented adjacent said zone during rotation of the roll such that each of said suction openings is independently subjected to the entire impact of said compact jet, said jet openings having a diameter as compared to the diameter of said suction roll openings in the ratio of approximately 5.35 to 1, whereby the water is projectedinto a suction opening against materials accumulated therein, moving the portion of the roll forming that opening out of alignment with the jet of water by the rotating of the roll at such speed that the water in the suction opening is thrown therefrom with the aid of centrifugal forces, continuing the rotation of the roll so as to move the openings into and out of axial alignment with the jet again, and repeating the steps until the accumulated materials have been cleared from the suction opening.

2. The art as described in claim 1 which includes, moving said jet along a path parallel to the axis of said suction roll to clean circumferential portions thereof progressively in an axial direction.

3. The art as described in claim 2 which includes, observing the zone in which the jet impacts the roll, and moving said jet axially of the roll when there has been a substantial disappearance of fog in said zone.

4. In a machine for making a web of paperboard or the like having a rotatably mounted suction roll said suction roll being free of any felt wrapped wholly therearound, said suction roll including a cylindrical wall with suction openings therein which are circular in cross section having their axes radial with respect to the suction roll and in which materials accumulate so as to impair the operation of said machine, apparatus for cleaning the materials from the suction openings in said suction roll comprising, a nozzle having a circular jet opening therein of substantially smaller diameter than the diameter of said suction openings wherein the ratio of the diameter of each of said suction openings to the diameter of said jet opening is approximately 5.35 to 1 means for delivering water under pressure to said nozzle and through said jet opening to form a compact stream of water directed outwardly of said nozzle, and support means supporting said nozzle adjacent individual suction opening presented adjacent said nozzle during the rotation of said roll whereby each of said suction openings is independently subjected to the entire impact of said compact jet as the respective suction openings are presented adjacent said nozzle to remove accumulated material therein.

5. Apparatus as described in claim 4 wherein said suction openings are of a diameter of the order of 56 inch and said jet opening has a diameter of the order of 0.07 inch.

6. Apparatus as described in claim 4 wherein said support means comprises, a moveable nozzle head, and a fixed rack means slidably supporting said head for movement substantially parallel with the axis of said suction roll.

7. Apparatus as described in claim 6 which includes a plurality of said nozzles of substantially identical construction and operation and mounted in said nozzle head.

8. Apparatus as described in claim 6 wherein said rack comprises a cylindrical member having a slot therein in which said nozzle is positioned.

9. Apparatus as described in claim 8 which includes a rigid pipe connected to said nozzle head.

10. Apparatus as described in claim 9 which includes a flexible tube connected to said pipe.

11. Apparatus as described in claim 4 wherein said nozzle has a circular nozzle opening of a diameter of the order of 0.07 inch.

12. Apparatus as described in claim 4 wherein said nozzle is positioned in close proximity to the peripheral surface of said suction roll adjacent the zone where said peripheral surface moves away from the web.

13. Apparatus as described in claim 12 wherein said suction roll has a peripheral wall with a thickness which is greater than V2 inch and is solid except for said suction openings and wherein said nozzle is positioned not more than H. inches from said peripheral wall.

I I i i i 

2. The art as described in claim 1 which includes, moving said jet along a path parallel to the axis of said suction roll to clean circumferential portions thereof progressively in an axial direction.
 3. The art as described in claim 2 which includes, observing the zone in which the jet impacts the roll, and moving said jet axially of the roll when there has been a substantial disappearance of fog in said zone.
 4. In a machine for making a web of paperboard or the like having a rotatably mounted suction roll said suction roll being free of any felt wrapped wholly therearound, said suction roll including a cylindrical wall with suction openings therein which are circular in cross section having their axes radial with respect to the suction roll and in which materials accumulate so as to impair the operation of said machine, apparatus for cleaning the materials from the suction openings in said suction roll comprising, a nozzle having a circular jet opening therein of substantially smaller diameter than the diameter of said suction openings wherein the ratio of the diameter of each of said suction openings to the diameter of said jet opening is approximately 5.35 to 1 means for delivering water under pressure to said nozzle and through said jet opening to form a compact stream of water directed outwardly of said nozzle, and support means supporting said nozzle adjacent said roll to project said compact stream radially against the surface of said roll and into each respective independent and individual suction opening presented adjacent said nozzle during the rotation of said roll whereby each of said suction openings is independently subjected to the entire impact of said compact jet as the respective suction openings are presented adjacent said nozzle to remove accumulated material therein.
 5. Apparatus as described in claim 4 wherein said suction openings are of a diameter of the order of 3/8 inch and said jet opening has a diameter of the order of 0.07 inch.
 6. Apparatus as described in claim 4 wherein said support means comprises, a moveable nozzle head, and a fixed rack means slidably supporting said head for movement substantially parallel with the axis of said suction roll.
 7. Apparatus as described in claim 6 which includes a plurality of said nozzles of substantially identical construction and operation and mounted in said nozzle head.
 8. Apparatus as described in claim 6 wherein said rack comprises a cylindrical member having a slot therein in which said nozzle is positioned.
 9. Apparatus as described in claim 8 which includes a rigid pipe connected to said nozzle head.
 10. Apparatus as described in claim 9 which includes a flexible tube connected to said pipe.
 11. Apparatus as described in claim 4 wherein said nozzle has a circular nozzle opening of a diameter of the order of 0.07 inch.
 12. Apparatus as described in claim 4 wherein said nozzle is positioned in close proximity to the peripheral surface of said suction roll adjacent the zone where said peripheral surface moves away from the web.
 13. Apparatus as described in claim 12 wherein said suction roll has a peripheral wall with a thickness which is greater than 1/2 inch and is solid except for said suction openings and wherein said nozzle is positioned not more than 1 1/4 inches from said peripheral wall. 